Intestinal surgery in small animals: historical foundations, current thinking, and future horizons

Miniaturized implantable temperature sensors for the long-term monitoring of chronic intestinal inflammation

Diagnosing and monitoring inflammatory bowel diseases, such as Crohn's disease, involves the use of endoscopic imaging, biopsies and serology. These infrequent tests cannot, however, identify sudden onsets and severe flare-ups to facilitate early intervention. Hence, about 70% of patients with Crohn's disease require surgical intestinal resections in their lifetime. Here we report wireless, miniaturized and implantable temperature sensors for the real-time chronic monitoring of disease progression, which we tested for nearly 4 months in a mouse model of Crohn's-disease-like ileitis. Local measurements of intestinal temperature via intraperitoneally implanted sensors held in place against abdominal muscular tissue via two sutures showed the development of ultradian rhythms at approximately 5 weeks before the visual emergence of inflammatory skip lesions. The ultradian rhythms showed correlations with variations in the concentrations of stress hormones and inflammatory cytokines in blood. Decreasing average temperatures over the span of approximately 23 weeks were accompanied by an increasing percentage of inflammatory species in ileal lesions. These miniaturized temperature sensors may aid the early treatment of inflammatory bowel diseases upon the detection of episodic flare-ups.

Stapled functional end-to-end intestinal anastomosis with endovascular gastrointestinal anastomosis staplers in cats and small dogs

OBJECTIVES

To investigate the use of endovascular gastrointestinal stapling devices to perform intestinal functional end-to-end stapled anastomosis in small dogs and cats.

MATERIALS AND METHODS

Medical records of dogs (≤10 kg) and cats that underwent intestinal resection and functional end-to-end stapled anastomosis with an endovascular gastrointestinal anastomosis (endovascular-GIA) stapling device at five small animal referral centres between April 2014 and September 2023 were retrospectively reviewed. Data including clinical findings, surgical technique, histopathology and complications were collected. A minimum follow-up of 10 days was required. Patients with follow-up of less than 10 days were included if they developed a major complication. Outcome was obtained from assessing the clinical records and contacting the referring veterinarians or owners. Estimated survival was generated according to the Kaplan-Meier method. Differences between survival curves were tested by log-rank test.

RESULTS

Twenty-five patients (10 dogs and 15 cats) were included. The median bodyweight was 4.6 kg (range 2.6 to 10 kg). Nine patients were diagnosed with intestinal neoplasia, 16 with non-neoplastic intestinal disease. The median follow-up was 126 days (range 18 to 896 days). Five patients developed minor postoperative complications, including three superficial surgical site infections. No major postoperative complications were reported. Eighteen patients were alive at the end of the study, one patient was lost to follow-up. Kaplan-Meier estimated median survival time was not reached. Survival was significantly longer for patients with non-neoplastic versus neoplastic intestinal.

CLINICAL SIGNIFICANCE

The study suggests that the use of endovascular gastrointestinal anastomosis staplers is safe and effective to perform intestinal functional end-to-end stapled anastomosis in dogs ≤10 kg and cats.

Chitosan thread in the healing of the cecal wall of rabbits (Oryctolagus cuniculus) submitted to cecorrhaphy

The development and evaluation of synthesis materials are crucial to reducing the morbidity and magnitude of post-enterorrhaphy surgical complications. Despite the possibility of production, chitosan thread has not yet been used in enterorrhaphy, and its effects on intestinal healing have not been evaluated. Therefore, this study aimed to evaluate the effects of chitosan thread on the intestinal wall repair of rabbits submitted to cecorrhaphy. For this, 42 rabbits were allocated into two groups with 21 animals. One group was submitted to cecorrhaphy with chitosan suture thread (CG) and the other with poliglecaprone suture thread (PG). The occurrence of postoperative complications, the intensity of edema, cellular response, formation of granulation tissue, as well as the deposition and maturation of collagen fibers, and the intensity of vascular endothelial growth factor (VEGF-α) expression, were evaluated during the intestinal wall repair process. The evaluations occurred on the 5th, 15th, and 25th postoperative (PO) days. The animals did not develop peritonitis, but adherence was observed in six animals from CG and seven from PG, with no difference between groups. The polymorphonuclear infiltrate showed higher intensity and higher amount of type III collagen fibers in CG on the 15th PO day. In contrast, a lower amount of type I collagen fibers was observed in CG samples on the 25th PO day. Therefore, the chitosan thread used for cecorrhaphy in rabbits results in minimal postoperative complications, presents biocompatibility, and bioactively assists the tissue repair process of the cecal wall, inducing minimal tissue reaction, stimulating the deposition of type III collagen fibers in the proliferative phase, with sustained VEGF-α expression, but with reduced deposition of type I fibers, indicating a delay in collagen maturation.

Epiploic foramen entrapment in a dog

OBJECTIVE

To report small intestinal herniation through the epiploic foramen in a dog.

ANIMALS

Nine-year-old male castrated Shih Tzu.

STUDY DESIGN

Case report.

METHODS

The dog presented with an 8-year history of vomiting and regurgitation and acute onset of melena, lethargy, anorexia, anemia, and suspected gastrointestinal mass or obstruction on prereferral imaging. Abnormalities on abdominal radiographs included a large, midcaudal soft tissue structure and cranial displacement and segmental dilation of the small intestine. On abdominal ultrasound, severe gastric dilation, jejunal tortuosity and stacking, and peritoneal effusion were observed. Epiploic herniation of the small intestine and segmental jejunal devitalization was diagnosed on exploratory laparotomy, and the dog underwent hernia reduction, jejunal resection and anastomosis, and nasogastric tube placement.

RESULTS

Severe gastric distention and atony persisted 24 h after surgery, despite medical management. The dog was taken to surgery for decompressive gastrotomy and placement of gastrostomy and nasojejunostomy tubes for postoperative decompression and feeding, respectively. Three days after the original surgery, the dog developed a septic abdomen from anastomotic dehiscence and underwent jejunal resection and anastomosis and peritoneal drain placement. Gastric dysmotility gradually resolved with the administration of motility stimulants, removal of gastric residual volume, and nutritional support via nasojejunostomy tube feedings. Three months after discharge, the dog was clinically normal.

CONCLUSION

Epiploic foramen entrapment should be considered a type of herniation in dogs. Clinical suspicion should be raised in dogs with unresolving regurgitation and vomiting, visceral displacement, and stacking and distension of small intestine.

Clinical outcomes of the use of unidirectional barbed sutures in gastrointestinal surgery for dogs and cats: A retrospective study

OBJECTIVE

To report the clinical outcomes of gastrointestinal surgery using unidirectional barbed sutures in single-layer appositional closure in dogs and cats.

STUDY DESIGN

Retrospective and descriptive study.

SAMPLE POPULATION

Twenty-six client-owned dogs; three client-owned cats.

METHODS

Medical records of dogs and cats that received gastrointestinal surgery closed with unidirectional barbed sutures were reviewed to collect information on signalment, physical examinations, diagnostics, surgical procedures, and complications. Short- and long-term follow-up information was collected from the medical records, the owners, or the referring veterinarians.

RESULTS

Six gastrotomies, 21 enterotomies, and nine enterectomies were closed with a simple continuous pattern with unidirectional barbed glycomer 631 sutures. Nine dogs had multiple surgical sites closed with unidirectional barbed sutures. None of the cases in the study developed leakage, dehiscence, or septic peritonitis during the 14-day short-term follow up. Long-term follow up information was collected for 19 patients. The median long-term follow-up time was 1076 days (range: 20-2179 days). Two dogs had intestinal obstruction due to strictures at the surgical site 20 and 27 days after surgery. Both were resolved with an enterectomy of the original surgical site.

CONCLUSION

Unidirectional barbed suture was not associated with a risk of leakage or dehiscence after gastrointestinal surgery in dogs and cats. However, strictures may develop in the long term.

CLINICAL SIGNIFICANCE

Unidirectional barbed sutures can be used during gastrointestinal surgery in client-owned dogs and cats. Further investigation of the role of unidirectional barbed sutures leading to abscess, fibrosis, or stricture is necessary.

Surgical Anatomy of the Gastrointestinal Tract in Cats

In cats, the gastrointestinal tract is one of the regions in which surgical procedures are most frequently performed by veterinary surgeons; therefore, knowledge of the surgical anatomy of the feline gastrointestinal tract is of high importance. The main surgical procedures performed include gastrotomy, gastrectomy, enterotomy, and enterectomy, as well as procedures in the liver and pancreas. There are also anatomical differences between dogs and cats, increasing the need for deep knowledge of the anatomy treated in the different surgical approaches. The aim of the present review is to describe in detail the anatomy of the gastrointestinal tract in cats highlighting the anatomical regions of significant importance in different surgical procedures.

Laparoscopic single-layer running "trapezoid-shaped" suture versus mechanical stapling for esophagojejunostomy after total gastrectomy for gastric cancer: cost-effect analysis of propensity score-matched study cohorts

OBJECTIVES

Totally laparoscopic total gastrectomy has been developed with difficulty in intracorporeal esophagojejunostomy. Although mechanical stapling has been widely used for intracorporeal esophagojejunostomy, manual suture holds great promise with the emergence of high-resolution 3D vision and robotic surgery. After exploration of how to improve the safety and efficiency of intracorporeal suture for esophagojejunostomy, we recommended the technique of single-layer running "trapezoid-shaped" suture. The cost-effectiveness was analyzed by comparing with conventional mechanical stapling.

METHODS

The study retrospectively reviewed the patients undergoing laparoscopic gastrectomy for gastric cancer from January 2010 to December 2021. The patients were divided into two cohorts based on the methods of intracorporeal esophagojejunostomy: manual suture versus stapling suture. Propensity score matching was performed to match patients from the two cohorts at a ratio of 1:1. Then group comparison was made to determine whether manual suture was non-inferior to stapling suture in terms of operation time, anastomotic complications, postoperative hospital stay, and surgical cost.

RESULTS

The study included 582 patients with laparoscopic total gastrectomy. The manual and stapling suture for esophagojejunostomy were performed in 50 and 532 patients, respectively. In manual suture cohort, the median time for the whole operation and digestive tract reconstruction were 300 min and 110 min. There was no anastomotic bleeding and stenosis but two cases of anastomotic leak which occurred at 3 days after surgery. The median length of postoperative hospital stay was 11 days. After propensity score matching, group comparison yielded two variables with statistical significance: time for digestive tract reconstruction and surgery cost. The manual suture cohort spent less money but more time for esophagojejunostomy. Intriguingly, the learning curve of manual suture revealed that the time for digestive tract reconstruction was declined with accumulated number of operations.

CONCLUSIONS

Laparoscopic single-layer running "trapezoid-shaped" suture appears safe and cost-effective for intracorporeal esophagojejunostomy after total gastrectomy. Although the concern remains about prolonged operation time for beginners of performing the suture method, adequate practice is expected to shorten the operation time based on our learning curve analysis.

Ex vivo comparison of different thoracoabdominal stapler sizes for typhlectomy in canine cadavers

OBJECTIVE

To determine the influence of staple size on leakage pressure of typhlectomy sites in canine cadavers.

STUDY DESIGN

Randomized, experimental cadaveric study.

ANIMALS

Twenty-four fresh canine cadavers.

METHODS

Ileocecocolic segments were exteriorized following right paracostal laparotomy after euthanasia. Cecal base length and wall thickness were measured. Each cecum was randomly assigned to 1 of 3 groups (TA 30 V3 2.5 mm, TA 60 3.5 mm, and TA 60 4.8 mm). The cecal base was stapled and the cecum was removed. A 10 cm segment including the stapled cecal excision site was tested for initial leak pressure.

RESULTS

The mean ± standard deviation body weights across the groups were 18.7 ± 6.1 kg, 16.2 ± 7.5 kg, and 14.2 ± 5.5 kg for the TA 30 V3 2.5 mm, TA 60 3.5 mm, and TA 60 4.8 mm groups, respectively (P = .48). There were no differences for mean cecal base length or wall thickness. Mean initial leak pressure (ILP) across groups was 182 ± 111 mmHg (TA 30 V3 2.5 mm), 112 ± 57 mmHg (TA 60 3.5 mm), and 77 ± 60 mmHg (TA 60 4.8 mm) (P = .78).

CONCLUSION

Each stapler size that was evaluated resulted in a mean ILP in excess of typical intraluminal pressures under normal circumstances. There were no differences among groups.

CLINICAL SIGNIFICANCE

The results of this cadaveric study support the use of any of the stapler sizes evaluated in similarly sized dogs. A prospective study is needed to be able to correlate stapler size and clinical outcome.

Volume of saline (0.9% NaCl) solution required to reach maximum peristaltic pressure in cadaveric intact jejunal specimens from dogs of various sizes

OBJECTIVE

To compare the volume of saline (0.9% NaCl) solution required to reach a maximum intraluminal peristaltic pressure of 25 mm Hg in dogs of various sizes.

SAMPLES

25 grossly normal jejunal segments from 6 canine cadavers < 20 kg (small dogs) and 25 segments from 5 cadavers ≥ 20 kg (large dogs).

PROCEDURES

Jejunal specimens were obtained within 1.5 hours after euthanasia. Harvested tissue was transected into 12-cm-long segments, mesentery was trimmed, and each segment was measured from the antimesenteric to mesenteric serosal edges. A 10-cm segment was isolated with Doyen forceps, securing a pressure sleeve within the lumen. Intraluminal saline was infused, and the volume was recorded when a pressure of > 25 mm Hg was achieved. Data were analyzed only from specimens in which the pressure remained between 24 and 26 mm Hg for > 5 seconds.

RESULTS

Mean ± SD intestinal measurement for large dogs (17.82 ± 1.44 mm) was greater than that for small dogs (12.38 ± 1.38 mm) as was the volume of saline solution infused (17.56 ± 7.17 mL vs 3.28 ± 1.41 mL, respectively). The volume infused increased by 1.31 mL (95% CI, 1.08 to 1.18) for every 1-mm increase in intestinal measurement and by 1.06 mL (95% CI, 1.052 to 1.068) for every 1-kg increase in body weight.

CONCLUSIONS AND CLINICAL RELEVANCE

The volume of saline solution used for intestinal leak testing should be determined on the basis of patient intestinal measurement or body weight. In vivo studies are necessary to establish the optimal volume for intestinal leak testing.

Intraoperative surgeon probe inspection compared to leak testing for detecting gaps in canine jejunal continuous anastomoses: A cadaveric study

OBJECTIVE

To compare the detection of gaps in jejunal continuous anastomoses by probing (PT) versus leak testing (LT).

STUDY DESIGN

Experimental study.

ANIMALS

Normal jejunal segments (n = 24) from two fresh canine cadavers.

METHODS

Intestinal segments were randomly selected by four volunteers who created six simple continuous anastomoses: two constructs using standard technique with 2-3 mm suture spacing (ST, 8 total), and four constructs with one 4-mm gap (IG, 16 total). All 24 anastomoses were examined with PT (1 volunteer) prior to LT (3 volunteers). LT was performed within a maximal peristaltic pressure range (34-54 cmH₂ O). The presence and location of anastomotic leaks (L_A ) detected with LT were compared with gaps detected with PT.

RESULTS

Nineteen out of twenty-four (79.2%) samples had at least one probe drop, and four out of twenty-three (17.4%) samples leaked. LT results from one sample were excluded due to iatrogenic suture failure. PT was 100% sensitive (95% CI: 51.01, 100%) with a 100% negative predictive value (95% CI: 56.55, 100%) at detecting gaps compared with LT. The location of all L_A was accurately identified with PT and confirmed during LT.

CONCLUSION

PT was highly sensitive at detecting gaps compared with LT. All L_A were accurately detected by PT. None of the segments negative during PT leaked.

CLINICAL SIGNIFICANCE

The diagnostic value of PT appears adequate to recognize gaps in cadaveric small intestinal anastomoses. PT offers surgeons an alternative to detect suture gaps that may contribute to postoperative dehiscence of intestinal anastomoses.

A Review of Normal Intestinal Healing, Intestinal Anastomosis, and the Pathophysiology and Treatment of Intestinal Dehiscence in Foreign Body Obstructions in Dogs

Small intestinal anastomoses are commonly performed in veterinary medicine following resection of diseased or devitalized intestinal tissue. Traditionally, suture has been employed to anastomose intestinal ends. However, use of intestinal staplers has become increasingly popular due to the ability to produce a rapid anastomosis with purported superior healing properties. Under normal conditions, intestinal healing occurs in three phases: inflammatory, proliferative, and maturation. Dehiscence, a devastating consequence of intestinal anastomosis surgery, most often occurs during the inflammatory phase of healing where the biomechanical strength of the anastomosis is almost entirely dependent on the anastomotic technique (suture or staple line). The resulting septic peritonitis is associated with a staggering morbidity rate upwards of 85% secondary to the severe systemic aberrations and financial burden induced by septic peritonitis and requirement of a second surgery, respectively. Intraoperative and postoperative consideration of the multifactorial nature of dehiscence is required for successful patient management to mitigate recurrence. Moreover, intensive postoperative critical care management is necessitated and includes antibiotic and fluid therapy, vasopressor or colloidal support, and monitoring of the patient's fluid balance and cardiovascular status. An understanding of anastomotic techniques and their relation to intestinal healing will facilitate intraoperative decision-making and may minimize the occurrence of postoperative dehiscence.

The Pathophysiology of Small Intestinal Foreign Body Obstruction and Intraoperative Assessment of Tissue Viability in Dogs: A Review

Small intestinal foreign body obstructions occur commonly in dogs, accounting for 80% of all canine intestinal obstructions. Such obstructions induce local aberrations in secretion, absorption, and intestinal motility that can precipitate devastating systemic consequences, including a systemic inflammatory response, sepsis, and multiorgan dysfunction. Radiographic diagnosis is poorly sensitive relative to ultrasonography for diagnosing the presence of obstructive foreign material. Emergent surgical intervention is indicated for dogs with obstructive foreign material due to an inability to assess the degree of compromise of the intestinal wall that may precipitate intestinal perforation and to mitigate progression of life-threatening electrolyte and acid-base imbalances secondary to sequestration and emesis. Intraoperatively, an enterotomy or resection and anastomosis may be required to remove the obstructive material. A number of subjective and objective techniques for assessing the viability of intestinal tissue have been described due to the poor accuracy associated with surgeon assessment of color, peristalsis, pulsation, bleeding, and mural thickness alone. Such techniques have the potential to alter the surgeon's decision-making regarding performance of an enterotomy or resection and anastomosis, potentially reducing morbidity associated with intestinal surgery.

Influence of closure technique on leakage pressures in an ex vivo canine typhlectomy model

OBJECTIVE

To determine the influence of three closure techniques on leakage pressures of canine typhlectomies.

STUDY DESIGN

Experimental, ex vivo.

SAMPLE POPULATION

Grossly normal cecal segments from 24 adult canine cadavers.

METHODS

Typhlectomies were assigned to one of three closure techniques: simple continuous closure with a Parker-Kerr pattern with 4-0 polydioxanone (group 1), closure with a 60-mm gastrointestinal stapler loaded with a 3.8-mm staple cartridge (group 2), and placement of a Cushing suture to augment the stapled closure (group 3). The median (range) of initial leakage pressure (ILP) and maximum leakage pressure (MLP) was compared between groups along with leakage location.

RESULTS

Typhlectomies in group 3 leaked at higher ILP (310 mm Hg; 188-310) than those in groups 1 (43 mm Hg; 31-80) and 2 (109.5 mm Hg; 68-173; P < .0001). Maximum leakage pressure were greater in group 3 than in other groups (P < .0001). Leakage was detected in 20 of 24 (83%) typhlectomies, located at the incisional line in 13 of 24 (54%) specimens and from suture holes in seven of 24 (29%) specimens.

CONCLUSION

Placement of a Cushing suture pattern to augment stapled incisions improved the ability of typhlectomies to sustain pressure compared with sutured or stapled cadaveric specimens alone.

CLINICAL SIGNIFICANCE

These results provide evidence to support placement of a Cushing suture pattern to augment the staple line for typhlectomies in dogs, although in vivo studies are required to determine the clinical significance of these findings.